I managed to obtain a working system with Ubuntu 13.04, booting on µSD, rooting on SATA, after really few modifications of the great work of Focus (user from #cubieboard channel on irc.freenode.org). HDMI output works perfectly with my screens, using HDMI wire + DVI converter. I understood by these way, why in my previous test I didn’t have a good display. The wire should be pluged before booting. Plug a hdmi + dvi is not hot-plug in testing configurations.
With this images, there is no graphic acceleration (2D and 3d), so the SoC become quickly hot, you can touch the SoC with your finger and feel the heat in 2 to 4 seconds. Screensaver was one of the main reason of the energy waste in my case (use most of the two CPUs for blitting images.